<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      //   var year = +prompt('请输入年份：')
      //   if (year % 4 == 0 && year % 100 != 0 ||year % 400 == 0) {
      //       alert('您输入的年份是闰年')
      //   } else {
      //     alert('您输入的年份是平年')
      //   }

      //   var str = ''
      //   for (var i = 1; i <= 5; i++) {
      //     for (var j = 1; j <= 5; j++) {
      //       str = str + '★'
      //     }
      //     str = str + '\n'
      //   }
      //   console.log(str)
      var sum = 0
      var average = 0
      var count 
      for (var i = 1; i <= 100; i++) {
        if (i % 3 == 0) {
            sum = sum + i
        }
      }
      average = sum / 
    </script>
  </body>
</html>
